<?php
/**
 * XLinkPager class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2011 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * XLinkPager displays a list of hyperlinks that lead to different pages of target.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: XLinkPager.php 197 2011-12-13 09:20:35Z mole1230 $
 * @package system.web.widgets.pagers
 * @since 1.0
 */
class XLinkPager extends CBasePager
{
	const CSS_FIRST_PAGE = 'first';
	const CSS_LAST_PAGE = 'last';
	const CSS_PREVIOUS_PAGE = 'previous';
	const CSS_NEXT_PAGE = 'next';
	const CSS_INTERNAL_PAGE = 'page';
	const CSS_HIDDEN_PAGE = 'hidden';
	const CSS_SELECTED_PAGE = 'selected';
	
	/**
	 * @var integer maximum number of page buttons that can be displayed. Defaults to 10.
	 */
	public $maxButtonCount = 10;
	/**
	 * @var string the text label for the next page button. Defaults to 'Next &gt;'.
	 */
	public $nextPageLabel;
	/**
	 * @var string the text label for the previous page button. Defaults to '&lt; Previous'.
	 */
	public $prevPageLabel;
	/**
	 * @var string the text label for the first page button. Defaults to '&lt;&lt; First'.
	 */
	public $firstPageLabel;
	/**
	 * @var string the text label for the last page button. Defaults to 'Last &gt;&gt;'.
	 */
	public $lastPageLabel;
	/**
	 * @var string the text shown before page buttons. Defaults to 'Go to page: '.
	 */
	public $header;
	/**
	 * @var string the text shown after page buttons.
	 */
	public $footer = '';
	/**
	 * @var mixed the CSS file used for the widget. Defaults to null, meaning
	 * using the default CSS file included together with the widget.
	 * If false, no CSS file will be used. Otherwise, the specified CSS file
	 * will be included when using this widget.
	 */
	public $cssFile;
	/**
	 * @var array HTML attributes for the pager container tag.
	 */
	public $htmlOptions = array(
		'class' => 'pager-link'
	);
	
	/**
	 * Initializes the pager by setting some default property values.
	 */
	public function init()
	{
		if ($this->nextPageLabel === null)
			$this->nextPageLabel = Yii::t('yii', 'Next &gt;');
		if ($this->prevPageLabel === null)
			$this->prevPageLabel = Yii::t('yii', '&lt; Previous');
		if ($this->firstPageLabel === null)
			$this->firstPageLabel = Yii::t('yii', '&lt;&lt; First');
		if ($this->lastPageLabel === null)
			$this->lastPageLabel = Yii::t('yii', 'Last &gt;&gt;');
		if ($this->header === null)
			$this->header = Yii::t('yii', 'Go to page: ');
		
		if (!isset($this->htmlOptions['id']))
			$this->htmlOptions['id'] = $this->getId();
		if (!isset($this->htmlOptions['class']))
			$this->htmlOptions['class'] = 'yiiPager';
	}
	
	/**
	 * Executes the widget.
	 * This overrides the parent implementation by displaying the generated page buttons.
	 */
	public function run()
	{
		$buttons = $this->createPageButtons();
		if (empty($buttons))
			return;
		echo $this->header;
		echo CHtml::tag('ul', $this->htmlOptions, implode("\n", $buttons));
		echo $this->footer;
	}
	
	/**
	 * Creates the page buttons.
	 * @return array a list of page buttons (in HTML code).
	 */
	protected function createPageButtons()
	{
		if (($pageCount = $this->getPageCount()) <= 1)
			return array();
		
		list ($beginPage, $endPage) = $this->getPageRange();
		$currentPage = $this->getCurrentPage(false); // currentPage is calculated in getPageRange()
		$buttons = array();
		
		// first page
		$buttons[] = $this->createPageButton($this->firstPageLabel, 0, self::CSS_FIRST_PAGE, $currentPage <= 0, false);
		
		// prev page
		if (($page = $currentPage - 1) < 0)
			$page = 0;
		$buttons[] = $this->createPageButton($this->prevPageLabel, $page, self::CSS_PREVIOUS_PAGE, $currentPage <= 0, false);
		
		// internal pages
		for ($i = $beginPage; $i <= $endPage; ++$i)
			$buttons[] = $this->createPageButton($i + 1, $i, self::CSS_INTERNAL_PAGE, false, $i == $currentPage);
		
		// next page
		if (($page = $currentPage + 1) >= $pageCount - 1)
			$page = $pageCount - 1;
		$buttons[] = $this->createPageButton($this->nextPageLabel, $page, self::CSS_NEXT_PAGE, $currentPage >= $pageCount - 1, false);
		
		// last page
		$buttons[] = $this->createPageButton($this->lastPageLabel, $pageCount - 1, self::CSS_LAST_PAGE, $currentPage >= $pageCount - 1, false);
		
		return $buttons;
	}
	
	/**
	 * Creates a page button.
	 * You may override this method to customize the page buttons.
	 * @param string $label the text label for the button
	 * @param integer $page the page number
	 * @param string $class the CSS class for the page button. This could be 'page', 'first', 'last', 'next' or 'previous'.
	 * @param boolean $hidden whether this page button is visible
	 * @param boolean $selected whether this page button is selected
	 * @return string the generated button
	 */
	protected function createPageButton($label, $page, $class, $hidden, $selected)
	{
		if ($hidden || $selected)
			$class .= ' ' . ($hidden ? self::CSS_HIDDEN_PAGE : self::CSS_SELECTED_PAGE);
		return '<li class="' . $class . '">' . CHtml::link($label, $this->createPageUrl($page)) . '</li>';
	}
	
	/**
	 * @return array the begin and end pages that need to be displayed.
	 */
	protected function getPageRange()
	{
		$currentPage = $this->getCurrentPage();
		$pageCount = $this->getPageCount();
		
		$beginPage = max(0, $currentPage - (int) ($this->maxButtonCount / 2));
		if (($endPage = $beginPage + $this->maxButtonCount - 1) >= $pageCount) {
			$endPage = $pageCount - 1;
			$beginPage = max(0, $endPage - $this->maxButtonCount + 1);
		}
		return array(
			$beginPage, 
			$endPage
		);
	}
}
